Aggiunge il rilevamento di invio e apertura delle email di campagna.

Ogni destinatario mostra se la mail è partita e se è stata aperta, con conteggi in dashboard.

Co-authored-by: Cursor <cursoragent@cursor.com>

app/helpers/application_helper.rb

@@ -176,6 +176,19 @@ module ApplicationHelper
                 class: "inline-flex items-center rounded-md px-2 py-0.5 text-xs font-medium #{colors[status] || 'bg-zinc-100 text-zinc-700'}"
   end
 
+  def mailing_open_badge(recipient)
+    return unless recipient.status == "sent"
+
+    if recipient.opened?
+      content_tag :span, "Aperta",
+                  class: "inline-flex items-center rounded-md bg-violet-100 px-2 py-0.5 text-xs font-medium text-violet-800 dark:bg-violet-950 dark:text-violet-200",
+                  title: "Prima apertura #{format_dt(recipient.opened_at)}"
+    else
+      content_tag :span, "Non aperta",
+                  class: "inline-flex items-center rounded-md bg-zinc-100 px-2 py-0.5 text-xs font-medium text-zinc-600 dark:bg-zinc-800 dark:text-zinc-300"
+    end
+  end
+
   def ab_variant_badge(variant)
     return if variant.blank?